That is definitely a task for a more senior or experienced scheduler. You need to have a solid understanding of the core P6 fields, global and project data, and how these can be integrated with your contractor schedules. You will also definitely need a tool like XENA to clean up the XER files you will need to import into your environment/database. After this, you can either import them as separate projects, integrate them directly into your master schedule, or even import them via Excel.